Towable underwater vessel

ABSTRACT

The hull is shaped as a transverse drive producing body with a small aspect ratio while depth steering equipment is mounted on the stern. The vessel has a water displacement which creates a static residual lift force should the power to the vessel be shut off for any reason. This allows the vessel to surface automatically. The depth steering equipment is controlled over a coaxial tow cable.

United States Patent 1151 3,688,730

Ortlieb et al. Sept. 5, 1972 [54] TOWABLE UNDERWATER VESSEL [56] References Cited [72] Inventors: Dieter Orflieb, Unteruhldingen; UNITED STATES PATENTS 3 356 056 l2/l967 Lehmann ..1 14/16 R x 3,024,757 3/1962 Aschinger ..114/235 B Erich Birkhold; Horst Kling, both of 3 474 750 I 969 l Friedrichshafen a ofoermany O/l LeBeu...............l14/235 B X 3,034,468 5/l962 Aschinger 14/235 B X [73] Assignee: Dornier System GmbH,

Fnedflchshafen, Germany Primary Examiner-Trygve M. Blix 22 il Feb 24, 197.) Attorney-Kenyon & Kenyon Reilly Carr & Chapin 21 Appl. No.: 13,676 [57] ABSTRACT The hull is shaped as a transverse drive producing [30] F 8 Application Pnority body with a small aspect ratio while depth steering Feb. 25, I969 Germany ..P 19 09 242.3 equipment is mounted on the stem; The vessel has a water displacement which creates a static residual lift il ..114/235 force Should the power to the vesse| be shut off for [I l th I t If 581 Field of Search....l 14/235 13, 235 R, 16 R, 16 A any ream e aumma cally. The depth steering equipment is controlled over a coaxial tow cable.

BCIaEmSDraWingEgures Fig. 2b

INVENTORS: D/ETER On-n. 15a doAcH/M THoMns BYHORST S OCKBURGER ERICK BlRKHOL-D TOWABLE UNDERWATER VESSEL This invention relates to a steerable underwater vessel and particularly to an underwater toward vessel having dynamically acting lateral drive surfaces.

Underwater towed vessels have been known to consist of a hull and fin stubs which extend from opposite sides of the hull in the region of the center of gravity of the vessel in order to steer a path for different depths of immersion. For this purpose, the fin stubs have been pivotally mounted on the hull and have been controlled so as to be oriented into a suitable positive or negative angular position to obtain an upward or downward drive.

However, such vessels have had a number of drawbacks. For example, the hull has generally not contributed, or only contributes insignificantly, to the production of upward forces and, thus, the stub fins have been of great span. As a result, these vessels have been bulky and clumsy and because of their shape and length have tended to become caught in driftwood or the like. Also, in the event that the stub fins would collide with a foreign object, the long effective lever arm can easily lead to damage or destruction of the vessel. These vessels have also required great rudder shifting forces with corresponding expenditures of energy due to the position of the adjustable stub fins. Further, these vessels have been of relatively great weight.

Other underwater towed vessels have also been constructed with rigid fin elements which extend from a forward region of a hull for producing an upward or downward drive and with fins on the stern for depth steering. However, as above, these vessels have extremely bulky widely extending fins which have been disadvantageous. Likewise, these vessels have been of relatively great weight while taking a small volume of useful load. Moreover, the widely projecting fins have been sensitive to shock stresses.

Still other underwater towed vessels have been constructed with delta shaped supporting fins with a negative V setting on which trimmer tabs have been disposed. By means of the shape and design of such fins, a downward drive of pre-determined magnitude is obtained which, during towing, keeps the vessel at substantially one and the same depth of immersion as a function of the length of the two cable. Such a vessel, however, is not adapted to obtain a change in the immersed depth over a wide range during one mission. Consequently, for projects which are to be carried out at different depths during one mission, it has been necessary to provide different supporting fins for the vessel. Further, in the case of widely extending fin shapes that are susceptible to shocks, because of the design as a supporting fin, only a relatively small volume is available for a useful load.

Accordingly, it is an object of the invention to create an underwater towed vessel of compact construction without widely extending fins.

It is another object of the invention to provide an underwater vessel of small weight and large capacity for useful load.

It is another object of the invention to provide an underwater towed vessel which can attain any desired profile of immersion depth over a wide range even during a single mission.

Briefly, the invention provides an underwater towed vessel which is made entirely as a transverse drive producing body of small aspect ratio and which is provided with a rudder assembly that controls the towed vessel by a positive or negative change of angular setting. The vessel is such as to obtain a favorable ratio of useful volume to surface area, while requiring relatively little power for steering in order to change the attitude of the towed vessel and being of extremely compact form without widely extending adjustable surfaces for producing upward or downward drives. Thus, the towed vessel is able, even during a single mission, to cover a wide range of depths without changing the length of a tow cable towing the same or the towing speed. Further, because of the shape of the towed vessel, the danger of catching in driftwood or the like, and also the sensitivity to shocks, are substantially diminished. The towed vessel is light in weight, and its steering surfaces can be made relatively small.

A further characteristic of the invention is that the towed vessel has a displacement of water volume through which a static residual upward force is always acting on the vessel. Thus, the towed vessel, for example, in the event of rupture of the tow-cable or an interruption in the towing operation, can be carried automatically to the surface of the water, and there recovered.

In order to make longitudinal trimming possible, in accordance with a further characteristic of the invention, the attachment of the tow-cable to the vessel is adjustable in the direction of the longitudinal axis so as to always act on the most favorable point of the towed vessel. The length of the tow-cable is chosen so that the cable weight will cause the towed vessel to sink so far that the dynamic vertical forces needed to reach the minimum or maximum depth of immersion are substantially equal in magnitude.

These and other objects and advantages of the invention will become more apparent from the following detailed description and appended claims taken in conjunction with the accompanying drawing in which:

FIG. 1 illustrates an underwater towed vessel according to the invention in a side view;

FIG. 2 illustrates a plan view, partly sectioned lengthwise of the vessel of FIG. 1;

FIG. 2a illustrates an enlarged part of FIG. 2, i.e., the

adjustable bearing of the towing assembly sectioned lengthwise;

FIG. 2b represents a block diagram of the controls for the depth-steering fins.

FIG. 3 illustrates a cross-sectional view taken on line llllll of H0. 2.

Referring to FlGS. l and 2, the underwater vessel serves as a towed vessel, and is towed by a cable 17 from a towing vessel (not shown) and is intended to carry measuring instruments. The underwater vessel has a hull l which carries a keel 5 containing a weight on the underside for stabilization against rolling. The hull l is shaped, as shown, so as to present a small aspect ratio in the direction of forward motion, e.g. of a substantially elliptical profile having a width to the gross area ratio (blF) of from l to 0.2. ln addition, the hull 1 is shaped so as to have a water displacement volume sufficient to create a static residual lift force on the vessel which would cause the vessel to be bouyed to the surface of the water in the event the vessel is not subjected to dynamic submerging forces. The hull l contains a longitudinally-extending hollow beam 7 which is inserted in the center of the hull l to define an internal space or chamber 7' for housing measuring instruments and electronic devices for steering a course and for transmitting measurements. In addition, two box beams 8 are secured to the hollow beam 7 and extend diametrically outward running as far as a shell 2 defining the outer contour of the hull 1. These box beams 8 provide, on the one hand, for stiffening of the vessel and, on the other hand, for the attachment of pivot-pins 9. As a whole, the towed vessel is made as a transverse-drive-producing body with a small aspect ratio.

in order to provide for the towing of the vessel 1, a towing assembly 9' is secured on the pivot pins 9. This towing assembly 9 includes a forked towing bar 12 which is pivotally linked into the pivot pins 9, a forkhead 16, and a tow cable 17 which is attached to the fork head 16. The cable 17, for example, is made as a coaxial cable, and consists of the tow cable 17 and of electric conductors for supplying electric current to a depth-rudder operating motor 42 mounted in the vessel. The cable 17 also includes electric conductors for the transmission of measured values from the measuring instrument (not shown) within the hollow beam 7 to the towing vessel.

As illustrated in FIG. 2a, the hull l is provided with recesses 18 in which the pivot pins 9 are slidabiy mounted, in order to permit the position of the pivot pins 9 to be adjusted, and thus, the point at which the towing assembly 9 is linked to the vessel. Movable plates 20 are placed on the recesses 18. These movable plates 20 are provided with elongated slots 22 parallel to the longitudinal axis of the hull 1. Through the elongated slots 22 protrude screws 23, which can be screwed by means of their threads into the corresponding threaded holes of the box beam 8. By means of the heads 26 of the screws 23 the movable plates 20 can be fixed to the hull l in difl'erent positions relative to the longitudinal axis of the hull. The movable plates 20 are provided with the pivot pins 9 allowing the forked towing bars 12 of the towing assembly 9 to be pivoted. The forked towing bars 12 are secured by the nut 27 on the threaded part of the pivot pins 9. This makes it possible to vary the point of application of the tow-cable 17 to the towed vessel, and, for example, permits adaptation to the useful load. In order to make it possible to steer the towed vessel perfectly, and in order to achieve static stability, the point of application of the force from the cable 17 shall always be situated a certain distance ahead of the point where the dynamic upward or downward drive force acts.

Referring to FIGS. 2 and 3, the towed vessel also has a stern part 40, which carries depth steering equipment and which is fastened as a whole by quick-acting connectors (not shown) to the hull 1. The stem part 40 consists of a tubular part 41, which serves to house the motor 42 for operating depth rudders or depth steering fins 47. The stem part 40 moreover has side stabilizingfins 45 which are fastened to the tubular part 41. The depth-steering fins 47 are mounted on axles 48 which are coupled to drive shafts 52 of the fin-adjusting motor 42 so as to permit pivoting of the fins 47.

In the event that the cable 17 is damaged or that for some other reason no control signals are received by the fin-adjusting motor 42 controlling the depth-steering fins 47, the depth-steering fins 47 return from any angular position to their neutral position (FIG. 2b). Thus, in the event of a power interruption, the depthsteering fins 47 do not remain in a deflected position which would, e.g. cause lift-forces to act on the vessel. The means for returning the depth-steering fins 47 to their neutral position consist of a battery 30 mounted in the hull 1, a comparator 31 and a relay 32. in addition, there is a switch 33 operated by the relay 32. Via this switch 33 either the power supply of the cable 17 or the power supply 34 from the battery 30 is connected to the fin-adjusting motor 42. A potentiometer 35 is connected to the drive shaft of the motor 42. Depending on the position of the depth-steering fins 47, this potentiometer 35 introduces a corresponding voltage to the comparator 31 via an electrical feedback 36. In case of an interruption of the power supply via the cable 17, the relay 32 drops out and the battery 30 is connected to the motor 42 via the switch 33. If the depth-steering fins 47 have returned to their neutral position, the voltage supplied from the potentiometer 35 via the feedback 36 and the voltage supplied from the battery 30 are balanced at the comparator 31, i.e., the voltage from the comparator equals 0. The stem part 40 also has a pair of longitudinally elongated supporting elements 55 for mounting the outer ends of the respective axles 48 of the depth-steering fins 47 These supporting elements 55 are connected to a supporting ring 56, which surrounds the stern part 40 concentrically, and to which are also fastened the outer ends of the lateralstabilizing fins 45 via a second pair of like supporting elements 55. The stem part 40 and the supporting elements 55 extend out beyond the rear end of the vessel and thereby form feet so that the vessel can be set up vertically on the deck of the towing vessel or on sheltering vessels or on land.

In operation, because of the weight of the tow-cable 17 which is so designed, the towed vessel becomes sunk to a certain depth at which the dynamic vertical forces needed to reach minimum and maximum depths of immersion, respectively, are of approximately equal magnitude. If it is desired to move the towed vessel to a different immersed depth, then the depth-steering fins 47 are pivoted so as to impart a corresponding angular attitude to the towed vessel. Through the construction of the entire towed vessel as upward-drive or downwarddrive body, a corresponding vertical force acts dynamically on the vessel, and through this, the towed vessel is brought to the desired depth of immersion. Through the intermediary of electronic devices, it is possible to have the towed vessel automatically follow a course set from the towing vessel (not shown) over the coaxial cable 17. The course may, for example, run approximately triangularly with respect to the depth of immersion. It is also possible to follow a course at a desired depth by means of steering commands from the towing vessel.

Because of the residual lift force acting statically on the towed vessel, the vessei is bouyed automatically to the surface of the water in the event of an interruption of its towed travel or of a rupture of the tow-cable 17. The towed vessel can then be hooked on again to the towing vessel. This positively, avoids loss of a towed vessel.

In case the motor 42 does not receive any control signals, the depth-steering fins 47 return to their neutral position, as mentioned above. Thus, it is avoided that the depth-steering fins 47 remain in a position where they act on the hull 1 such as to cause its descent.

It is noted that a vessel made in accordance with the invention can be equipped with its own means of propulsion. The underwater vessel could then, for example, by means of remote control and through the intermediary of its depth-steering fins, travel a desired depth profile, or be brought to a desired depth of imm'ersion. it is finally noted that the body of the vessel can be described as a dynamic lifting body instead of by the alternative expression of transverse drive producing body.

What is claimed is:

l. A towable underwater vessel comprising a transverse drive producing hull of small aspect ratio (b /F), said aspect ratio being in the range of 1.0 to 0.2 wherein b is the span width of said hull and F is the area of the entire lifting surface of said hull, and a plurality of dynamically acting transverse drive surface means on said hull for adjusting the positive and negative angular attitude of the vessel, said means including a pair of adjustably mounted fins at the rear of said hull for creating a relatively large lever arm to the center of gravity of the vessel; and means for returning said fins into a neutral position and locking said fins therein in response to an interruption of the control signals transmitted by a towing vessel.

2. A towable underwater vessel as set forth in claim 1 wherein said hull has a water displacement volume sufficient to impose a static residual lift force continuously thereon.

3. A towable underwater vessel as set forth in claim I further comprising a towing assembly connected to said hull, said towing assembly being adjustably positionable longitudinally of said hull.

4. A towable underwater vessel as set forth in claim I further comprising actuating means on said hull for ad justing said drive surface means and a towing assembly connected to said hull and having a cable connected to said actuating means for transmitting steering pulses and power to said actuating means.

5. A towable underwater vessel as set forth in claim 1 further comprising a stabilizing keel on said hull.

6. A towable underwater vessel as set forth in claim I further comprising a plurality of supporting elements extending from the rear of said hull and supporting said drive surface means therein, said supporting elements being sized to support the vessel in an upright vertical position.

7. A towable underwater vessel as set forth in claim 1 wherein said hull includes a sealed hollow longitudinal beam defining a chamber therein, a pair of hollow beams extending laterally from said longitudinal beam and a shell enclosing said beams.

8. A towable underwater vessel comprising a transverse drive producing hull of small aspect ratio: a plurality of dynamically acting transverse drive surface means on said hull for adjusting the positive and negative angular attitude of the vessel, said means including a pair of adjustably mounted fins at the rear of said hull for qreatinfi a relatively large lever arm to the center of gravity of e vessel; an means for returmng said fins into a neutral position and locking said fins therein in response to an interruption of the control signals transmitted by a towing vessel. 

1. A towable underwater vessel comprising a transverse drive producing hull of small aspect ratio (b2/F), said aspect ratio being in the range of 1.0 to 0.2 wherein b is the span width of said hull and F is the area of the entire lifting surface of said hull, and a plurality of dynamically acting transverse drive surface means on said hull for adjusting the positive and negative angular attitude of the vessel, said means including a pair of adjustably mounted fins at the rear of said hull for creating a relatively large lever arm to the center of gravity of the vessel; and means for returning said fins into a neutral position and locking said fins therein in response to an interruption of the control signals transmitted by a towing vessel.
 2. A towable underwater vessel as set forth in claim 1 wherein said hull has a water displacement volume sufficient to impose a static residual lift force continuously thereon.
 3. A towable underwater vessel as set forth in claim 1 further comprising a towing assembly connected to said hull, said towing assembly being adjustably positionable longitudinally of said hull.
 4. A towable underwater vessel as set forth in claim 1 further comprising actuating means on said hull for adjusting said drive surface means and a towing assembly connected to said hull and having a cable connected to said actuating means for transmitting steering pulses and power to said actuating means.
 5. A towable underwater vessel as set forth in claim 1 further comprising a stabilizing keel on said hull.
 6. A towable underwater vessel as set forth in claim 1 further comprising a plurality of supporting elements extending from the rear of said hull and supporting said drive surface means therein, said supporting elements being sized to support the vessel in an upright vertical position.
 7. A towable underwater vessel as set forth in claim 1 wherein said hull includes a sealed hollow longitudinal beam defining a chamber therein, a pair of hollow beams extending laterally from said longitudinal beam and a shell enclosing said beams.
 8. A towable underwater vessel comprising a transverse drive producing hull of small aspect ratio: a plurality of dynamically acting transverse drive surface means on said hull for adjusting the positive and negative angular attitude of the vessel, said means including a pair of adjustably mounted fins at the rear of said hull for creating a relatively large lever arm to the center of gravity of the vessel; and means for returning said fins into a neutral position and locking said fins therein in response to an interruption of the control signals transmitted by a towing vessel. 